Happy Friday Hive!  

Signalment:  4 year old MN Sphynx cat

History:  Chronic 3 month history of squinting the right eye and discharge.  Was treated for a superficial ulcer in the right eye with Erythromycin three times a day but did not return for the recommended recheck exam.  Also has a history of an URI when first acquired as a kitten. 

Presented today like this:

So....What are we looking at here?  What in the world is that? 

This is a feline corneal sequestrum.  

My mantra...If its black and it's on the cornea of a cat, it's a sequestrum!

So what is black on a cat's cornea....yep, a sequestrum. 

Okay, now that we have established that, let's talk about seqeustra!  *That's the pleural 

Sequestra are focal regions of corneal necrosis 🤢 and typically occur secondary to chronic ulceration or chronic irritation on the corneal surface.   They can range in appearance from light brown to dark black and can be superficial or deep, extending in some cases to Descemet's membrane. 

Examples of causes of sequestra secondary to chronic ulceration or irritation include:

• Feline Herpes Virus (FHV-1) induced ulceration
• Entropion causing chronic corneal irritation
• Brachycephalic breed predisposition/ Exposure keratitis 
  • Resulting from macropalepbral fissure and lagophthalmia
• Palpebral or orbital neoplasia
• Distichia
• Qualitative and quantitative tear film disease

Treatment:

How do we treat this?  

The gold standard is surgical removal with a keratectomy.  This involves corneal surgery to remove the diseased corneal tissue and depending on depth, is often followed by corneal grafting with either a corneo-conjunctival transposition (CCT) or conjunctival pedicle graft (CPG).  

In cases where general anesthesia needs to be avoided, finances are limited or the sequestrum is superficial and the cat is relatively comfortable, use of a diamond burr to debride or remove some of the sequestrum and stimulate the body's natural response to resolve the issue may be possible. 

Some of these will slough on their own over time but that can take months! 

Preventing infection and achieving comfort is key.  Topical antibiotics and lubricating gels may help prevent/control infection and alleviate symptoms of foreign body sensation.  Pain control with systemic medication will help achieve comfort. 

Some sequestra are superficial and easy to address with minimal intervention. Some can be full thickness and result in perforation of the globe.  

The general rule is to try to get feline ulcers identified and treated appropriately so that an ulcer does not stick around long enough to develop into one of these! 

#coolcases

About the Guide: Kristin Miller Fischer, DVM, DACVO

Dr. Kristin Fischer is a board-certified veterinary ophthalmologist. She graduated from the University of Tennessee College of Veterinary Medicine in 2007 and completed a rotating general internship at VCA Alameda East Veterinary Hospital in Denver, CO. She then returned to Knoxville in 2009 to complete her ophthalmology residency at UTCVM. Dr. Fischer practices in South Carolina and works at Animal Eye Care of the Lowcountry. She loves the challenge of the complicated cases and the frequent connection between ophthalmology, internal medicine and neurology. Her favorite thing is returning sight to blind animals and then seeing them greet their families post-op!